There's been no contact with the man since then and neighbors on both sides of the Brandon home have been evacuated.

"We put engineering equipment into the sinkhole and didn't see anything compatible with life," Ms. Damico said. But Damico would not say that the man is presumed dead.

Damico said that, at the surface, she estimates the sinkhole is about 30 feet across but officials say the sinkhole spreads to about 100 feet across below the surface. Authorities were waiting for an engineering crew to bring monitoring equipment to determine the borders of the sinkhole, she said.

"The entire house is on the sinkhole," Damico said.

Janell Wheeler told the Tampa Bay Times she was inside the house with four other adults, a child, and two dogs when the sinkhole opened.

"It sounded like a car hit my house," she said.

It was dark. She remembered screams and one of her nephews rushing to rescue his brother, who was trapped in the debris.

Ms. Wheeler's house was condemned. The rest of the family went to a hotel, but she stayed behind with her dog, sleeping in her car.

Sinkholes are often caused by the underground erosion of salt beds or soluble sedimentary rocks, such as limestone or dolomite. Ground water flows through these rocks, creating subterranean caverns that can suddenly collapse.